Bird flu spreads ‘efficiently’ in ferrets, scientists warn amid growing fears it could spark another pandemic.
Experts called the discovery “deeply concerning” and claimed it shows the pathogen is one step closer to spreading to humans.
It is the first known study to clearly confirm that mammals can not only contract the disease individually, but also spread it to others.
However, deaths of infected mammals such as minks, foxes, raccoons and bears in recent months have suggested that this may have been the case.
H5N1 – the avian flu strain behind the current outbreak sweeping the world, believed to be the largest ever – is not easily transmitted between humans.
H5N1 – the avian flu strain behind the current outbreak sweeping the world – doesn’t spread easily between humans. But the research, currently being reviewed by the journal Nature, found that H5N1 “can cause fatal diseases in multiple mammalian species” and “direct contact” between ferrets can lead to “deadly consequences” (stock image)
But mutations in the virus that facilitate mammal-to-mammal transmission could change that, some experts fear.
There are fewer than 900 human cases of H5N1 worldwide, which kills nearly 50 percent of everyone it affects.
The virus is usually picked up through close contact with an infected bird, dead or alive.
Now new researchnot yet peer-reviewed, found that H5N1 “can cause fatal disease in multiple mammalian species.”
Canadian researchers, including some from government health agencies, infected ferrets with one of four H5N1 strains.
Ferrets were chosen for the study because they have a similar respiratory makeup to humans, giving experts an idea of how a virus would react to humans.
They found that “direct contact” with one strain of H5N1 isolated from an infected bird had “deadly consequences,” the paper added.
It raises the prospect that the strain may have “developed certain adaptations that allow higher rates of replication, pathogenicity and transmission.”
They warned that if such a species made the leap to humans, the consequences could be catastrophic.
“Because there is little to no population-wide H5-specific immunity, an H5N1 isolate capable of long-term transmission would jump a species to humans, likely representing a destructive infection in an immunologically naive population,” they wrote.
John Fulton, a pharmaceutical industry consultant and founder of BioNiagara, told MailOnline that H5N1 poses a threat “100 times worse than Covid.”
He added: “This discovery is of great concern and governments should take immediate action by identifying and mobilizing all high-potential production capacity for vaccines and therapies for the prevention and treatment of H5N1 bird flu.”
Some countries, including China, have been vaccinating against the H5N1 strain for years.
Some countries, including China, have been vaccinating against the H5N1 strain for years. Birds are vaccinated via an injection into the egg or a spray on chicks while they are still in the box
However, under UK health policy, vaccinating chickens is currently illegal. But the Animal and Plant Health Agency, a branch of DEFRA, is currently examining possible vaccine candidates for humans in the UK, should the virus spread to humans. “The number of laying hens available to produce eggs for vaccine production is already compromised and vulnerable to a complete destruction of the egg-producing herd, leaving us with limited production capacity,” said Mr Fulton.
Birds are vaccinated via an injection into the egg or a spray on chicks while they are still in the box.
However, under UK health policy, vaccinating chickens is currently illegal.
But the Animal and Plant Health Agency, a branch of DEFRA, is currently examining possible vaccine candidates for humans in the UK, should the virus spread to humans.
“The number of laying hens available to produce eggs for vaccine production has already been compromised and is vulnerable to a complete destruction of the egg-producing herd, leaving us with limited production capacity,” said Mr Fulton.
Vaccine makers GSK, Moderna and CSL Seqirus have begun developing new human injections to tackle the rapidly spreading virus strain.
Others, such as Sanofi, stock generic vaccines against the H5N1 virus that can be adapted to the currently circulating strain.
Like other forms of the flu, people can become infected if the virus gets into their eyes, nose, or mouth, or is inhaled.
But with bird flu, it usually occurs in people who spend a lot of time with infected creatures, such as bird handlers.
In early 2023, a wave of bird flu cases in humans has emerged.
Earlier this year, a Cambodian man and his daughter were diagnosed with H5N1.
Their cases caused international concern, with many experts fearing the infection was evidence that the virus had mutated to better infect humans after ripping through the world’s bird population.
Further testing revealed that the H5N1 strain was not spreading rapidly among the world’s wild birds among the Cambodian family, but instead a variant known to spread locally in the Prey Veng province in which they lived.
Since the ongoing outbreak broke out in October 2021, there has been only one case of a Briton becoming infected with H5N1.
Alan Gosling, a retired engineer in Devon, became infected with the virus in early 2022 after his ducks, some of which lived in his home, became infected.
The UK Health Security Agency (UKHSA) has currently set the threat level to level three as there is “evidence” of changes in the virus genome that could cause a “mammal infection”, it said.
Any “sustained” transmission of the pathogen from mammal to mammal would raise the threat level to four, while it would rise to five from human to human.